19993887 has 18 divisors (see below), whose sum is σ = 30682808. Its totient is φ = 12543552.

The previous prime is 19993849. The next prime is 19993889. The reversal of 19993887 is 78839991.

19993887 = T₂₁₈ + T₂₁₉ + ... + T₅₀₆.

It is not a de Polignac number, because 19993887 - 2⁶ = 19993823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19993889) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1243 + ... + 6444.

Almost surely, 2^19993887 is an apocalyptic number.

19993887 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

19993887 is a deficient number, since it is larger than the sum of its proper divisors (10688921).

19993887 is a wasteful number, since it uses less digits than its factorization.

19993887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7727 (or 7707 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 19993887 is about 4471.4524485898. The cubic root of 19993887 is about 271.4141034499.

It can be divided in two parts, 1999 and 3887, that added together give a triangular number (5886 = T₁₀₈).

The spelling of 19993887 in words is "nineteen million, nine hundred ninety-three thousand, eight hundred eighty-seven".